Tubular-bag machine having a gas-adjusting device, and gas-adjusting device for such a tubular-bag machine

ABSTRACT

The invention specifies an in particular horizontal tubular-bag machine ( 5 ) in which objects ( 2 ) which are provided for packaging are conveyed along a conveying direction ( 6 ) by means of a conveying apparatus ( 51 ). The tubular-bag machine ( 5 ) has an apparatus ( 50, 43 ) for producing from a packaging sheet material ( 12 ) a packaging tube ( 13 ) extending in the conveying direction ( 6 ), and also has a longitudinal-connection device ( 53, 54 ) and a transverse-connection device ( 44 ) for producing longitudinal and transverse connections in the packaging tube ( 13 ). Also provided is a gas-adjusting device ( 8 ) with an introduction head ( 80 ) for engaging in the packaging tube ( 13 ) in a direction transverse to the conveying direction, wherein the introduction head ( 80 ) has a first gas-passage opening ( 802, 804, 805, 807, 808 ) and at least one second gas-passage opening ( 802, 804, 805, 807, 808 ) by way of which a gas is fed into the packaging tube ( 13 ) or removed therefrom.

BACKGROUND OF THE INVENTION

The present invention relates to a tubular-bag machine having a gas-adjusting device. The gas-adjusting device is particularly used to remove air from a packaging tube formed by the tubular-bag machine and/or to feed gas into the packaging tube. The invention further relates to a gas-adjusting device and a method for adjusting the gas content of the packagings for such a tubular-bag machine.

Tubular-bag machines are used in the packaging industry for packaging products in a packaging sheet material. It is thereby necessary to differentiate basically between horizontal and vertical tubular-bag machines.

In the case of horizontal packaging machines, a packaging sheet material that is unwound from a reel and placed around products or product groups, which are supplied in a row, is formed to a tube which laterally encloses these products or product groups. The packaging tube and the products to be packaged are usually moved together and continuously via a conveying means in a direction which is substantially horizontal in relation to the direction of gravitational force. The two longitudinal sheet edge regions of the packaging sheet material are then placed together with the respective inner surfaces thereof to form a so-called finseal, which also can be referred to as a longitudinal sealing seam, and are adhesively bonded, sealed or welded to one another. The packaging tube formed in this manner is subsequently welded transversely to the finseal using two transverse heat-sealing jaw pairs which are disposed opposite one another and is separated at the same time or in a subsequent processing step into individual packagings.

In the case of vertical packaging machines, the packaging tube usually extends, in contrast, substantially in the direction of gravitational force, and the machine allows the product to be packaged to drop into the packaging tube after the longitudinal sealing seam as well as the transverse sealing seam at the bottom of the packaging has already been formed.

The problem that exists with tubular-bag machines is that too much air is enclosed in the manufactured packagings, which can lead to bloated packagings. In order to prevent this, the tubular-bag machines often comprise suction devices, by means of which the air is directly evacuated out of the packaging tube prior to sealing.

The Swiss patent specification CH 436 102 describes a device for packaging units of goods, in which air is evacuated from the packaging tube by means of a lance or pipe, which extends in the conveying direction, in the proximity of the transverse welded joint. The disadvantage of such systems, in which a lance protrudes into the packaging tube, is that the lance in the packaging tube requires a relatively large space and therefore increases the amount of packaging material for the packagings being produced. When packaging small and elongated products, there is additionally the risk that the products will be displaced in the packaging tube if contact is made with the pipe. This effect is additionally increased with higher speeds of the machine. In the event of a malfunction of the tubular-bag machine and a subsequent intervention by the operating personnel, the reinsertion of the lance into the packaging tube is furthermore relatively arduous; and there is additionally the risk of the lance being damaged in the process.

Particularly with products which change their properties when contact is made with oxygen or, respectively, air, a protective atmosphere is further required in the packagings in order to increase the shelf life of the products. This can, for example, relate to fresh foods, baked goods and pharmaceutical products, such as particularly, for example, tablets in blister packs. In order to provide a protective atmosphere in the packagings, the tubular-bag machines often accordingly have apparatuses for supplying a protective gas, in particular nitrogen, to the packaging immediately prior to sealing. The oxygen is simultaneously displaced as a result of supplying the protective gas. In addition, suction devices are, however, often present to evacuate the air or, respectively, oxygen separately from the supplying of the protective gas. In this way, the protective gas atmosphere can be optimally adjusted; and the packagings can be prevented from markedly distending due to the gas that has been supplied.

In the Swiss patent specification CH 610 260, a horizontal tubular-bag machine is described, in which a flat nozzle extends from below between the two longitudinal sheet edge regions of the packaging tube directly upstream of a heated pair of welding rollers which is used to weld the longitudinal seam. Air is evacuated through this flat nozzle out of the packaging tube. Additional flat nozzles can be provided in order to introduce a compressed gas into the packaging tube in order to produce a protective atmosphere in the packagings. Pairs of rollers are disposed in each case between the individual flat nozzles in order to ensure a sealing of the packaging tube, so that no external air can ingress into the tube between the flat nozzles and no gas can escape from the tube. This construction comprising a plurality of flat nozzles and roller pairs disposed therebetween is relatively complex and requires much space. Furthermore, the formation of leakage openings between the individual flat nozzles is unavoidable.

In the tubular-bag machines mentioned above, the quantities of discharged air as well as gas supplied has to be adjusted each time as a function of the respective packaging volume, the objects to be packaged, the spacing between products on the conveying means, the operating speed of the machine, etc. This adjustment has to be carried out and optimized in each case manually by the operating personal, which constitutes a relatively arduous and time intensive process.

SUMMARY OF THE INVENTION

It is therefore the aim of the present invention to specify a tubular-bag machine having a gas-adjusting device, which has a simple and cost effective construction and which enables the protective atmosphere in the packagings to be efficiently adjusted and, furthermore, can also be used at higher outputs.

The term “gas” refers below in each case to a substance and/or a mixture which is present in the gaseous aggregate state. This can, for example, relate to nitrogen or also air. A gas-passage opening therefore refers to an opening which is suitable for a gas flow of, for example, nitrogen or air in an arbitrary direction.

The present invention therefore provides a tubular-bag machine, which relates particularly to a horizontal tubular-bag machine and which is used to package objects by means of a packaging sheet material, comprising:

a conveying apparatus for conveying objects, which are provided for packaging by means of the tubular-bag machine, along a conveying direction;

an apparatus for producing from a packaging sheet material a packaging tube extending in the conveying direction;

a longitudinal-connection device for producing a longitudinal connection of the packaging tube along a longitudinal sheet edge region of the packaging sheet material;

a transverse-connection device for producing transverse connections in the packaging sheet material which extend substantially transversely to the longitudinal direction; and

a gas-adjusting device with an introduction head for engaging in the packaging tube in a direction transverse to the conveying direction, wherein the introduction head has a first gas-passage opening by way of which a gas is fed into the packaging tube or removed therefrom.

The introduction head additionally has at least one second gas-passage opening by way of which a gas is fed into the packaging tube or removed therefrom.

The provision of at least two gas-passage openings in the introduction head allows for a very simple and cost effective construction of the tubular-bag machine. The gas-adjusting device can, in particular, have overall a very compact configuration; thus enabling said device to be retrofitted as a simple connection piece in a tubular-bag machine of the prior art. By providing at least two gas-passage openings, the gas-adjusting device requires a minimum amount of space and can be simply disposed, for example, directly between two pairs of rollers. In particular, no additional pairs of rollers are required to provide sealing between the individual gas-passage openings. Simple guide plates, which are disposed on the sides of the gas-adjusting device, are, for example, already sufficient to meet this end.

A further advantage of the tubular-bag machine mentioned above is that the gas-passage openings can be spaced apart from one another in the conveying direction at arbitrary distances. In so doing, an air evacuation and a gas feed in the packaging tube can particularly be implemented at arbitrary distances to one another, whereby inter alia an optimal regulation of the air evacuation quantity and/or the gas feed quantity is enabled. A plurality of gas-passage openings can in fact be provided for the air evacuation and/or a plurality of gas-passage openings for the gas feed in the introduction head; thus enabling the distance between the air evacuation and the gas feed to be varied even during ongoing operation of the tubular-bag machine by only a portion of the gas-passage openings being selected for the air evacuation or the gas feed. Alternatively, a plurality of gas-passage openings for the air evacuation and/or a plurality of gas-passage openings for the gas feed can also simultaneously be used in any arbitrary order. The gas-adjusting device and therefore the tubular-bag machine can thus be used in a versatile and flexible manner.

The introduction head is particularly designed to engage in the packaging tube such that the gas can be introduced into the packaging tube or removed therefrom substantially in a direction which is perpendicular to the conveying direction. The first and the second gas-passage opening can both be used to feed gas or to remove gas. One of the two gas-passage openings, however, is preferably used to feed the gas and the other to remove the gas.

The introduction head preferably has at least another third gas-passage opening in addition to the first and the second gas-passage opening. Besides being used for the air evacuation or the gas feed, the third gas-passage opening can, for example, also be used for a pressure measurement or other measurements. It is also conceivable for different gases to be introduced into the packaging tube via the different gas-passage openings. As an option, gases having different temperatures can also be introduced through the different gas-passage openings into the packaging tube and mixed therein with one another in order to thus, e.g., regulate the temperature in the tube. This can be advantageous if the gas, which is heated in this manner, in the finished packaging is later cooled down, and the volume of the packaging is thereby decreased.

In the regions between the individual gas-passage openings, an optimal sealing of the packaging tube with respect to the gas-adjusting device can be ensured outwardly to the surrounding atmosphere because the lateral surfaces of the packaging tube or, respectively, the longitudinal sheet edge regions of the packaging sheet material do not have to be repeatedly first brought together and then separated again by means of the pairs of rollers. The tubular-bag machine can therefore be particularly constructed in such a manner that practically no leakage openings occur in the region of the gas-adjusting device.

In order to achieve an optimal sealing, the tubular-bag machine usually has pressing elements and/or guide elements which are disposed laterally in the region of the gas-adjusting device or in the conveying direction directly upstream and/or downstream of the gas-adjusting device and are used to press the longitudinal sheet edge regions of the packaging sheet material against the gas-adjusting device or to guide the same along said gas-adjusting device. To this end, pressing rollers and/or laterally mounted brushes are provided. In a particularly advantageous manner, said rollers or brushes are resiliently pressed against the gas-adjusting device. For that reason, the pressing rollers can particularly have outer surfaces that are made of elastic material. Guide elements, such as particularly guide rollers, can be alternatively or additionally provided, which are used to guide the longitudinal sheet edge regions along the gas-adjusting device, such that said sheet edge regions rest against the introduction head and, in particular, rest against said introduction head in the region disposed downstream of the gas-passage opening in the conveying direction and lie against one another immediately downstream of the gas-adjusting device in such a way that essentially no connection (leak) can occur in this region between the packaging bag and the surrounding environment. In order to facilitate the insertion of a new packaging tube into the tubular-bag machine, it is advantageous if the pressing and/or guide elements can be, particularly hydraulically or pneumatically, moved apart from one another, in particular pivoted apart from one another.

An efficient regulation of the air evacuation and/or the gas feed can particularly be provided in a construction having practically no leakage openings and gas-passage openings that are disposed closely to one another. To this end, the tubular-bag machine preferably comprises a control and/or regulation unit which is designed to optimize an air discharge quantity and/or gas feed quantity as a function of the volume of the packaging and/or of the properties of the objects to be packaged and/or of the conveying settings of the conveying apparatus and/or of values which are measured by sensors on the gas-adjusting device. The quantity of gas being currently fed or discharged can be precisely set by the control and/or regulation unit. The conveying settings relate particularly to the speed with which the objects to be packaged are transported as well as to the distances at which the objects to be packaged are spaced apart from one another. Upon starting the tubular-bag machine, after an interruption of said machine's operation or if said machine has been stopped or the conveying speed has been changed during ongoing operation, the adjustment control, the air evacuation and/or the gas feed can continually be adapted to the changing conveying speed. In the case of the sensors which are mounted advantageously in close proximity to or particularly directly on the introduction head of the gas-adjusting device, said sensors can relate to pressure sensors or to sensors that measure the oxygen content in the packaging tube. Provision can, for example, be made for ultrasonic sensors or optical sensors. By a sensor being disposed closely to or directly on the introduction head in the region of the gas-passage openings, the distances over which the gas has to be transported from the packaging tube to the sensor are reduced, which enables a fast and more precise measurement. A fast measurement particularly refers in this context to the fact that less than 12 packagings, preferably less than 6 packagings, most preferably less than 3 packagings, are produced during the time it takes for a measurement result to be firmly established with regard to a certain packaging. The machine speed is thereby advantageously set at at least 50 packagings per minute, more advantageously at at least 150 packagings per minute and most advantageously at at least 200 packagings per minute. The control is advantageously set such that the quantity of gas fed corresponds as precisely as possible to the quantity of gas effectively required for the packagings. The protective atmosphere in the packagings can thus be set in an extremely efficient manner.

A tubular-bag machine can also, of course, have two or more such gas-adjusting devices, between which, in particular, respectively one seal can be implemented by means of the roller pairs.

The tubular-bag machine preferably continuously forms the tubular bag, i.e. the packaging tube and the tubular bag formed therefrom are preferably moved at a substantially constant speed in the tubular-bag machine in the conveying direction. “At a substantially constant speed” refers in this context to the fact that the film web and therefore the packaging tube does not come to rest in order to form the individual packagings, and particularly the speed of said film web is not changed. Process-related changes in speed can, however, occur, particularly in order to compensate for irregular product feed or the lack of product for packaging, so that no empty packagings result etc. The gas-adjusting device advantageously constitutes a stationary unit of the tubular-bag machine, which is fixedly mounted with respect to the frame of the tubular-bag machine.

A chain comprising drivers is usually used as the conveying apparatus for feeding the objects, wherein each driver transports one or a plurality of objects and delivers the objects into the packaging tube at that location where said packaging tube is formed. Other conveying apparatuses are, however, conceivable, such as, e.g., a plurality of magnetically driven linear motors which transport the objects. Roller pairs, which are disposed beneath a running surface and are oppositely pressed against the longitudinal sheet edge regions, are typically used as the conveying apparatus for the packaging tube comprising the objects situated therein. The running surface generally has a longitudinal slot to accommodate the longitudinal sheet edge regions of the packaging sheet material.

The longitudinal-connection device can particularly relate to a longitudinal sealing device which usually comprises heatable pairs of rollers. During the longitudinal connection of the packaging tube, the two sheet edge regions of the packaging sheet material, the inner surfaces of which have been laid on top of each other, are connected to one another using the longitudinal-connection device. The connection which thereby results is known to the person skilled in the art by the terms “finseal” or “fin seam”. “Lap seals” or “overlapping seams” are likewise also known, in which the inner surface of the one sheet edge region is laid over the outer surface of the other sheet edge region and are thus connected to one another. The longitudinal-connection device can basically be designed to produce finseal connections or also lap seal connections.

The transverse-connection device can particularly relate to a rotating or follower transverse sealing device, which, for example, has heatable jaws which can press from opposite sides against the packaging tube. The transverse-connection device advantageously has a separation apparatus that is known from the prior art, such as cutting or crush cutting knives, which is provided to separate the packagings from one another in the region of the transverse connections.

The longitudinal-/transverse-connection device is advantageously designed as a longitudinal/transverse sealing device. A sealing device generally refers to a device which joins two material layers by applying pressure and/or heat. The sealing device seals the packaging tube by sealing elements pressing the sheet edge regions from opposite sides of the packaging bag together. The sheet edge regions can thereby preferably comprise sealing layers which promote a connection of the material layers. The sealing elements are preferably heated and besides providing pressure give off heat to the packaging sheet layers. Further methods are known which promote the sealing of the packaging sheet layers, such as, for example, subjecting the sealing jaws to high frequency vibrations (ultrasonic sealing).

The introduction head usually has a longitudinal extension which extends in the conveying direction, and the second gas-passage opening is disposed downstream of the first gas-passage opening in the longitudinal direction.

In a preferred embodiment, the introduction head has a first continuous bearing surface and a second continuous bearing surface, wherein the first bearing surface is used to support a first lateral surface of the packaging tube; and the second bearing surface is used to support a second lateral surface of the packaging tube which lies opposite the first lateral surface, and wherein the first gas-passage opening and the second gas-passage opening are disposed between these two continuous bearing surfaces. The bearing surfaces can each, but not necessarily, be designed as a plane.

The introduction head advantageously comprises a main section, within which the first bearing surface and the second bearing surface extend substantially parallel to one another. The first gas-passage opening and the second gas-passage opening are then particularly advantageously disposed in this main section. It is thereby ensured that the lateral surfaces of the packaging tube fit tightly in the region of the gas-passage opening.

The introduction head preferably comprises a first wedge-shaped section, within which the first bearing surface and the second bearing surface converge in a wedge-shaped manner in the conveying direction or, respectively, the longitudinal direction. This first wedge-shaped section is advantageously disposed between two rollers of the longitudinal-connection device, which are used to seal the longitudinal sheet edge regions of the packaging sheet material. Guide rollers can alternatively or additionally be provided, which guide the longitudinal sheet edge regions towards one another in the conveying direction directly downstream of the wedge-shaped section. The lateral surfaces of the packaging bag can thereby be slowly brought together again after passing the region comprising the gas-passage openings, while avoiding leakage openings.

The introduction head furthermore comprises alternatively or additionally a second wedge-shaped section, within which the first bearing surface and the second bearing surface converge in a wedge-shaped manner in a direction oriented against the longitudinal direction or, respectively, against the conveying direction. The longitudinal sheet edge regions of the packaging sheet material can thereby be slowly spread apart without leakage openings occurring. Of course, the gas-passage openings can also be disposed in the regions of the first and/or second wedge-shaped section.

In the event that a main section comprising parallel bearing surfaces and/or a first wedge-shaped section and/or a second web-shaped section are present, the transitions between the first and the second bearing surface are preferably designed continuously in each case. The transition regions can, however, also be formed by means of an edge. A gas-passage opening is preferably disposed within the first and/or the second wedge-shaped section. This gas-passage opening is particularly well suited for measuring the gas properties because said opening can be disposed directly in the region of the longitudinal- and/or transverse-connection device.

In a modification to the invention, the first gas-passage opening and/or the second gas-passage opening is designed as an elongated hole, which has a significantly larger extension in the longitudinal direction of the introduction head than in a direction perpendicular thereto. The extension of the elongated hole in the longitudinal direction of the introduction head, i.e. in the conveying direction, is advantageously many times greater than in a direction perpendicular thereto. The elongated hole preferably has a width between 1 mm and 20 mm, particularly preferably between 3 mm and 10 mm. The elongated hole preferably has a length between 10 mm and 100 mm, particularly preferably between 20 mm and 50 mm. In so doing, the gas-passage opening can be adapted to the form and the movement of the packaging tube, whereby an efficient gas setting is achieved.

The gas-adjusting device usually comprises at least one connection fitting, which is connected to the first gas-passage opening or to the second gas-passage opening and which is used to connect a gas feed or a gas discharge apparatus. This connection fitting then preferably extends outwards substantially perpendicularly to the first lateral bearing surface and/or to the second lateral bearing surface. In a particularly preferable manner, the connection fitting extends outwards in a direction oriented horizontally and perpendicularly to the conveying direction. The connection of vacuum lines, gas feed lines and/or measuring lines to the gas-adjusting device is thereby facilitated. A separate connection fitting is preferably provided for each of the gas-passage openings. It is, however, also conceivable for a single connection fitting to be connected to two or more gas-passage openings. In addition, the gas-adjusting device can also have a regulating valve with which the gas feed and/or evacuation quantity can be directly controlled.

The first gas-passage opening, which is advantageously disposed upstream of the second gas-passage opening in the conveying direction, preferably is used to evacuate gas out of the packaging tube and is particularly delimited by an orifice structure which is unevenly formed in the opening direction of the first gas-passage opening. The orifice structure can particularly have a corrugated design. Such an orifice structure prevents the objects to be packaged from being drawn to the gas-passage opening by the vacuum and as a result laterally sealing off said opening, which would impair the evacuation of the air or of a gas out of the packaging tube and could even lead to the objects lodging at the gas-passage opening. A gas-passage opening being used for the gas feed can also be delimited by an orifice structure which is uneven and, in particular, corrugated in order to ensure the introduction of gas even at that moment at which the object to be packaged is situated directly above the opening.

The introduction head advantageously has a continuous, respectively uninterrupted, substantially planar orifice surface within which the first gas-passage opening as well as the second gas-passage opening and particularly, if present, further gas-passage openings outwardly discharge. The air evacuation and the gas feed can thereby take place in the same plane.

The first and/or the second gas-passage opening each extend in the orifice region thereof at an angle which is inclined in the longitudinal direction relative to the orifice surface. In so doing, the gas flow direction into the packaging tube can be influenced primarily with regard to gas feed openings.

A gas-adjusting device for a tubular-bag machine, which is embodied as described above, is furthermore specified. The gas-adjusting device is used to adjust the gas content of packagings which are produced from a packaging tube by means of the tubular-bag machine. The gas-adjusting device has an introduction head for laterally engaging in the packaging tube, wherein the introduction head has a first gas-passage opening and at least one second gas-passage opening by way of which a gas is fed into the packaging tube or removed therefrom. The introduction head is therefore designed to engage in the packaging tube in a direction substantially transverse to the conveying direction.

The introduction head advantageously has bearing surfaces to support lateral surfaces of the packaging tube, wherein the bearing surfaces extend continuously over approximately the entire length of the introduction head. It is even possible for the introduction head to be entirely formed from one piece.

A method for adjusting the gas content of packagings is furthermore specified, said packagings being produced from a packaging tube, which is conveyed in a conveying direction, by means of a tubular-bag machine that is particularly embodied as described above, wherein gas is removed from the packaging tube through a lateral opening formed on said packaging tube, and wherein gas is simultaneously introduced into the packaging tube through the same lateral opening.

When restarting the machine, it is preferred that gas in each case is initially introduced in an increased quantity through the gas-passage openings into the packaging tube before the actual production of the packagings begins. As a result, the oxygen which is situated in the packaging tube can be removed. Optionally, air can be simultaneously evacuated through a further gas-passage opening. After a preset time or when the gas measurement provides a tolerable measurement result, the machine begins preferably automatically with the production of the packagings. After starting the machine, it is very preferential if, alternately in each case for short intervals of time, only gas is evacuated from the packaging tube and only gas is fed into the same. This can particularly be done until the gas measurement produces a tolerable result. Subsequently, the machine begins in an advantageous manner to automatically produce the packagings.

During an interruption of the packaging production of short duration, the gas feed and/or gas evacuation is advantageously maintained (e.g. for a certain amount of time and/or until the operating state of the machine changes) in order to prevent the packaging tube from filling with air again by providing a kind of gas curtain. In order to save gas, a reduced amount of gas can thereby be fed and removed.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below with the aid of the drawings, which are only used for explanation and are not to be interpreted in a restrictive way. In the drawings:

FIG. 1 shows a perspective view of a horizontal tubular-bag machine according to the prior art;

FIG. 2 shows a side view of a schematically depicted, inventive horizontal tubular-bag machine;

FIG. 3 shows a horizontal section of the tubular-bag machine depicted in FIG. 2;

FIG. 4 shows a perspective partial view of an inventive tubular-bag machine having a gas-adjusting device, wherein the running surface and the packaging sheet material are omitted;

FIG. 5 shows a cross-sectional view of a schematically depicted tubular-bag machine according to the invention in a plane extending transversely to the conveying direction of the tubular-bag machine;

FIG. 6 shows a perspective view of the gas-adjusting device according to the invention shown in FIG. 4;

FIG. 7 shows a sectional view in the plane VII-VII of the gas-adjusting device shown in FIG. 6;

FIG. 8 shows a sectional view in the plane VIII-VIII of the gas-adjusting device shown in FIG. 6;

FIG. 9 shows a sectional view in the plane IX-IX of the gas-adjusting device shown in FIG. 8;

FIG. 10 shows a sectional view in the plane X-X of the gas-adjusting device shown in FIG. 8; and

FIG. 11 shows a top view of a gas-adjusting device and of unheated pairs of rollers, heated pairs of rollers and a guide unit of a tubular-bag machine.

DETAILED DESCRIPTION

A horizontal tubular-bag machine is depicted in FIG. 1, as said machine is well known from the prior art. The tubular-bag machine 4 has a film roll 10 as packaging material 1. The film roll 10 contains a packaging sheet material 12.

The tubular-bag machine 4 comprises a frame 40 with operating and display elements 42 mounted thereon. A running surface 400, which has a longitudinal slot 401, is provided on the top side of the tubular-bag machine 4. The longitudinal slot 401 is used to accommodate the longitudinal sheet edge regions of the packaging sheet material 12 formed to a packaging tube during transport of the objects to be packaged along the longitudinal direction of the running surface 400. The tubular-bag machine 4 depicted in FIG. 1 furthermore comprises a longitudinal-connection device, which is not visible here and is disposed beneath the running surface 400, as well as a transverse-connection and separation device 44, which, in a known manner, welds the packaging tube 13 transversely to the conveying direction between the objects to be packaged and separates said packaging tube into individual packagings. The transverse-connection and separation device 44 relates in the present case to a follower transverse-connection and separation device 44 from the prior art, which moves with the packaging tube in each case over a certain distance in the conveying direction in order to produce a transverse connection.

The gas-adjusting device according to the invention, as said device is described below, can readily be used in the tubular-bag machine from the prior art that is shown in FIG. 1.

FIGS. 2 and 3 depict schematically a tubular-bag machine 5 according to the invention. Components or constituent parts which have a similar effect or fulfill the same function as the corresponding components shown in FIG. 1 are in each case indicated with the same reference sign.

As is typical with tubular-bag machines of the prior art, a packaging tube 13 is also formed in the tubular-bag machine 5 shown in FIGS. 2 and 3 by means of a forming area 43 consisting of a packaging sheet material 12 wound on a film roll 10. The packaging tube 13 laterally, i.e. transversely to the conveying direction, encloses objects 2 to be packaged, which are transported in a row by means of a conveyor chain 51 along a conveying direction (arrow 6) into the forming area 43. The conveyor chain 51 has drivers 510 for transporting the objects 2. The packaging sheet material 12 is fed to the forming area 43 via deflection rollers 50. The two longitudinal sheet edge regions 120 of the packaging sheet material 12 are brought together on the bottom side of the objects 2 to be packaged, so that said sheet edge regions each rest against one another with the inner surface thereof and ultimately form a fin seam.

The packaging tube 13 together with the objects 2 to be packaged is fed along the conveying direction indicated with the aid of the arrow 6 to an unheated pair of rollers 52, which press the two longitudinal sheet edge regions 120 of the packaged sheet material 12 against one another from opposite directions in order to seal the packaging tube 13 laterally or, respectively, downwards. A gas-adjusting device 8 is disposed in the conveying direction 6 immediately downstream of the unheated pair of rollers 52. The gas-adjusting device 8 protrudes with an introduction head 80 from below between the two longitudinal sheet edge regions 120 of the packaging sheet material 12 into a lateral opening of the packaging tube 13. In so doing, the gas-adjusting device 8 preferably protrudes to such an extent into the packaging tube that the top face of the running surface 400 is substantially almost flush with the top face of the gas-adjusting device 8.

A first heatable pair of rollers 53 is disposed in the conveying direction 6 immediately downstream of the gas-adjusting device 8. The pair of rollers 53 press the two longitudinal sheet edge regions 120 of the packaging tube 13 sealingly against one another and heat the same such that said sheet edge regions are welded to one another. The pairs of rollers 52 and 53 are particularly disposed immediately upstream or downstream of the gas-adjusting device 8 in such a way that air is prevented from escaping out of and/or penetrating into the packaging tube 13 in the region between the gas-adjusting device 8 and the pair of rollers 52 and 53. Lateral pressing elements 56 (see FIGS. 3 and 5) are provided in the region of the gas-adjusting device 8 in order to press the longitudinal sheet edge regions 120 of the packaging sheet material 12 from opposite sides against the gas-adjusting device 8. Pairs of rollers comprising preferably elastically formed outer surfaces are, for example, conceivable as pressing elements 56, as is depicted in FIG. 3. The pressing elements 56 are particularly used to seal the packaging bag 13 outwardly with respect to the gas-adjusting device 8.

A preheater 57, which preheats the packaging tube 13 to an increased temperature that is suitable for the final sealing, is disposed beneath the running surface 400 downstream of the heatable pair of rollers 53 in the conveying direction 6. The finseal is eventually finally welded by means of a downstream second heatable pair of rollers 54. The heatable pairs of rollers 53 and 54 and the preheater 57 therefore jointly form a longitudinal-connection device. The pairs of rollers 52, 53 and 54, however, also constitute a conveying apparatus for conveying the packaging tube 13 and consequently the objects 2 to be packaged along the conveying direction.

A rotating transverse-connection and separation device 44 is provided here downstream of the longitudinal-connection device 53, 54 and 57 in the conveying direction. The transverse-connection and separation device 44 comprises oppositely arranged, rotating shafts 440 and 441 with jaws 442 and 443 mounted thereon. Knives 444, which are in each case mounted on the jaws 442 and 443, are used to cut the packaging tube transversely to the conveying direction 6. As a result, packagings 3 are formed which are subsequently received by a conveyor belt 55 located downstream of the transverse-connection and separation device 44 for further processing.

As can be seen in FIG. 2, the tubular-bag machine 5 has a vacuum pump 93 which is used to evacuate air out of the packaging tube 13 through the gas-adjusting device 8 and via a vacuum line 90. In order to produce a protective atmosphere in the packagings 3, a gas supply apparatus 94 comprising a gas conveying means, respectively ventilator, is provided in order to introduce an appropriate gas, such as especially nitrogen, via a gas feed line 91 and through the gas-adjusting device 8 into the packaging tube 13.

In particular in the region of the gas-adjusting device 8 which is located in the conveying direction 6 at the very back, measurements can be performed by means of one or a plurality of sensors in order to obtain information with regard to the gas content present in this region in the packaging tube 13. For example, the pressure or the oxygen content in the packaging tube 13 can be analyzed. An ultrasonic measurement or an optical measurement can, for example, even be performed in order to check the presence, the correct position and or the spacing of the individual objects 2 with respect to one another. The results of these measurements are transmitted via a measurement line 92 to the evaluation unit 95. The transmission can take place, for example, electrically or also optically via a fiber optic cable. By means of the measurement line 92, gas could alternatively also be directly evacuated out of the packaging tube 13 and through the gas-adjusting device in order to be analyzed in the evaluation unit 95 by a sensor.

Based on the results of the evaluation unit 95 and/or on the adjusting parameters, which were entered into the system via the operating and display elements 42, a control of the vacuum pump 93 and the gas supply apparatus 94 can be performed by means of a control unit 96 in order to optimize the gas content prevailing in the packaging tube 13 and particularly in the packagings 3. To this end, the control unit 96 is in connection with the evaluation unit 95, the gas supply apparatus 94 and the vacuum pump 93. The lines 90, 91, 92, the vacuum pump 93, the gas supply apparatus 94 and the units 95, 96 collectively form a gas feed and evacuation apparatus 9.

In FIG. 4, a partial view of the tubular-bag machine 5 is shown, wherein the arrangement of the gas-adjusting device 8 within the tubular-bag machine 5 can be particularly well seen. The packaging tube 13 as well as the pressing elements 56 are omitted in FIG. 4 for reasons of clarity. As was already described with regard to FIGS. 2 and 3, the gas-adjusting device 8 is disposed directly between the unheated pair of rollers 52 and the heated pair of rollers 53 which are used to longitudinally seal the packaging tube 13. The introduction head 80 protrudes substantially parallel to the rotational axes 520, 530 and 540 of the pairs of rollers 52, 53 and 54 upwards into the packaging tube 13.

The gas-adjusting device 8 has a vacuum connection fitting 810 as well as two connection fittings 811 and 812 for the gas feed, which extend outwardly, substantially perpendicularly to the conveying direction 6 and horizontally between the pairs of rollers 52 and 53. As can be seen in FIG. 4, the preheater 57 disposed immediately downstream of the first heatable pair of rollers 53 has a longitudinal slot, which is used to accommodate the two longitudinal sheet edge regions 120 of the packaging sheet material 12; thus enabling a preheating of these sheet edge regions 120 to take place in the preheater 57.

In FIG. 4, the pressing elements 56, which press the longitudinal sheet edge regions 120 of the packaging sheet material 12 at the introduction head 80, are not depicted. The pressing elements 56 can, however, be seen in FIG. 5. The pressing elements 56 can be designed as rollers and/or as guide elements, such as, e.g. guide plates, which can extend, particularly in the conveying direction, across the entire length of the introduction head 80.

As can be seen in FIG. 5, the packaging tube 13 together with the top side of the introduction head 80 delimits an interior space 7, which is sealed off to the outside and in which the object 2 to be packaged is accommodated, in the region of the gas-adjusting device 8.

A gas-adjusting device 8 according to an inventive embodiment is shown in FIGS. 6 to 10. The gas-adjusting device 8 has an introduction head 80 which is designed here entirely as one piece and which is suited for engaging in the packaging tube 13 in a direction transverse to the conveying direction 6. The introduction head 80 has two lateral bearing surfaces 800 which are used to support the two longitudinal sheet edge regions 120 of the packaging sheet material 12. Because the lateral bearing surfaces 800 each extend in the conveying direction 6 continuously over the entire length of said introduction head, it is possible for the lateral surfaces of the packaging tube 13 to rest opposite one another on the introduction head 80 across the entire length of said introduction head 80.

The introduction head 80 has a main section, inside of which the two bearing surfaces 800 extend completely parallel to one another. Respectively one wedge-shaped section 801, in which the lateral bearing surfaces 800, starting from the main section, each converge in a wedge-shaped manner, adjoins said main section in the conveying direction as well as in the direction oriented oppositely to the conveying direction. The wedge-shaped sections 801 are used to spread apart the lateral surfaces of the packaging tube 13 and subsequently to bring said lateral surfaces together.

Within the main section, the introduction head 80 comprises an evacuation opening 802 as well as two gas supply openings 804 and 805, which are arranged consecutively in the conveying direction. In so doing, the gas supply openings 804 and 805 are disposed downstream of the evacuation opening 802 in the conveying direction. The evacuation opening 802 as well as the gas supply openings 804 and 805 are each designed as an elongated hole, which has a substantially larger extension in the longitudinal direction of the introduction head 80 or, respectively, in the conveying direction than in a direction perpendicular thereto. The openings 802, 804 and 805 each open out in the region of a planarly designed orifice surface 809 which forms the top side of the introduction head 80. As a result of the two gas supply openings 804 and 805 being present, the distance of the gas supply opening to the evacuation opening 802 or, respectively, the surface of the entire effective gas supply opening can be flexibly adjusted.

In order to ensure an evacuation of air out of the packaging tube 13 by means of the evacuation opening 802 even in the case of an object 2 to be packaged being situated directly in the region of the evacuation opening 802, the evacuation opening 802 is laterally delimited by an orifice structure 806 that is corrugated towards the top.

The introduction head 80 has a circular sensor opening 803, which is suited to accommodating a sensor, between the evacuation opening 802 and the gas supply opening 804. In this case, the sensor can relate, for example, to an ultrasonic sensor or to an optical sensor for measuring the distance between the objects 2 to be packaged.

An additional gas supply opening 807, which is dimensioned significantly smaller in comparison to the gas supply openings 804 and 805, is provided in the wedge-shaped section 801 that adjoins the main section immediately adjacent to the evacuation opening 802. The gas supply opening 807 is used particularly to introduce gas in the conveying direction both immediately in front of and behind the objects 2 to be packaged. The efficiency which relates to the feed of gas into the packaging tube 13 can be improved by means of said additional gas supply opening 807.

A sensor opening 808, which is used to measure the oxygen content in the packaging tube 13, is provided in the wedge-shaped section 801 disposed in the conveying direction at the very back of the introduction head 80. The sensor opening 808 can be used for inserting a sensor or evacuating gas which is then supplied to a sensor. As a result of the sensor opening 808 being disposed in the conveying direction in close proximity to the gas-passage openings 802, 804 and 805, the system can quickly react to a measurement result that does not meet the quality specifications, and the relevant packaging(s) 3 is/are, for example, separated out in the region of the conveyor belt 55 by means of compressed air. A purging device is thus advantageously arranged in the region of the conveyor belt 55. Alternatively, the machine can also, of course, be stopped if required. As a result, it can particularly be ensured that a large number of defective packagings have not been produced before the measurement result is certain and the system can react to the problem.

A distributor housing 81 is mounted to the bottom of the introduction head 80, which forms a portion of the gas-adjusting device 8. This distributor housing 81 has an air collection chamber 813 as well as gas collection chambers 814 and 815, into which the evacuation opening 802 or the gas supply openings 804 and 805 open. In order to facilitate an evacuation of air through the evacuation opening 802 and the air collection chamber 813, a vacuum fitting 810, which opens into the air collection chamber 813, is provided on the distributor housing 81 for connecting the vacuum line 90. Analogous thereto, connection fittings 811 and 812 are provided which are used to connect gas feed lines 91 and open into the gas collection chamber 814 or 815. The vacuum connection fitting 810 as well as the connection fittings 811, 812 for the gas feed extend in each case towards the outside substantially perpendicularly to the lateral bearing surfaces 800 in the region of the main section of the introduction head.

In a downward direction, i.e. on the side opposite to the introduction head 80, the gas-adjusting device 8 has a base plate 817 which seals the air collection chamber 813 as well as the gas collection chambers 814 and 815 in the downward direction. Two additional connection fittings 816 are mounted to the base plate 817, which extend downwards perpendicularly to the base plate 817. The first of these connection fittings 816, which can be seen in FIG. 8, is associated with the sensor opening 808. The second of these additional connection fittings 816 cannot be seen in the figures. Said fitting 816 extends parallel to the first connection fitting 816 in a downward direction and is associated with the gas supply opening 807. The connection fittings 816 are used to connect lines which are associated with the gas supply opening 807 or the sensor opening 808. The base plate 817 is attached from below to the distributor housing 81 by means of screws 818.

A gas-adjusting device is depicted in a top view in FIG. 11. Elements having the same or similar function or, respectively, effect as corresponding elements specified in FIGS. 1 to 10 have in each case the same reference sign as those in FIGS. 1 to 10. The tubular-bag machine has in this case a guide unit 100 disposed in the region of the gas-adjusting device. This guide unit 100 is used to guide the sheet edge regions 120 of the packaging sheet material 12 tightly along the bearing surfaces 800 that lie flush against the introduction head 80 and to bring the sheet edge regions 120 together immediately downstream of the introduction head 80 such that a leak cannot occur between said introduction head 80 and the pair of sealing rollers 53. In so doing, the guide unit 100 particularly ensures that the sheet edge regions 120 rest tightly against the bearing surfaces 800 in the region of the gas supply opening 804 or, in the event of a plurality of gas supply openings being present, in the region of the gas supply openings 804, 805 as well as in the regions of the introduction head 80 which are disposed downstream thereof in the conveying direction 6. It is likewise ensured that the two sheet edge regions 120 lie tightly against one another immediately downstream of the introduction head 80 and the pair of sealing rollers 53 and that there is not any gas and/or air moving out of or, respectively, into the inner region of the packaging tube 13. Leakage openings are prevented between the sheet edge regions 120 and the introduction head 80 if said sheet edge regions fit tightly against the bearing surfaces 800 of the introduction head.

The guide unit 100 has two guide rollers 101 which subsequently bring the sheet edge regions together against the introduction head 80 from opposite sides. The guide rollers 101 are therefore disposed downstream of the introduction head 80 along the conveying direction 6. In order that packaging sheet materials 12 having unequally thick sheet edge regions 120 can be fed without difficulty between the guide rollers 101, said packaging sheet materials are minimally spaced apart from one another also during regular operation. The sheet edge regions 120 are thus generally fed through the guide rollers 101 facing one another, however not pressed against one another. Likewise, thicker sheet edge regions at splice sites, as they arise when joining packaging sheet portions during packaging sheet production, can therefore also be processed without difficulty.

In order to facilitate the insertion of new packaging sheet material 12 into the tubular-bag machine, the guide rollers 101 can be pivoted away from one another. To this end, said guide rollers are each mounted at a first end of a lever arm 103. A spring force is preferably applied respectively to both lever arms 103 such that said lever arms push the guide rollers 101 towards one another. The lever arms 103 can each be, for example hydraulically or pneumatically, pivoted about pivot axis by means of a cylinder 102. For this purpose, the cylinders 102 each have a piston which is connected to the respective second end of the lever arm 103. The guide rollers 101 can also be pivoted apart from one another during the continuous operation of the machine, when very thick splice sites are present in the packaging sheet material, as has been described above.

Of course, the invention described here is not limited to the aforementioned embodiment and a plurality of modifications is possible. The gas-adjusting device could also, for example, have a smaller number of evacuation or gas supply openings. For example, only two gas supply openings or only one gas supply opening and one evacuation opening could be provided. At least two openings must, however, be present which allow gas to pass through the introduction head. The two lateral bearing surfaces of the introduction head do not necessarily have to disposed parallel to one another in a main section. It would also be conceivable that the two wedge-shaped sections 801 directly adjoin one another and that the evacuation and/or gas supply openings are disposed within these wedge-shaped sections. The lateral bearing surfaces of the introduction head could furthermore be designed such that each is inclined in the vertical direction. Instead of only one single object, a plurality of objects could also be jointly packed in respectively one packaging. The gas-adjusting device could furthermore also be used exclusively to evacuate air from the packaging tube or exclusively to feed gas into the packaging tube. The tubular-bag machine could in this case also have a lance protruding into the packaging tube in addition to the gas-adjusting device, said lance implementing the gas supply or the air evacuation. Instead of a continuous operation, the tubular-bag machine can also be operated in a pulsed manner. A plurality of other modifications is conceivable. 

1. A tubular-bag machine (5) configured to package objects (2) by means of a packaging sheet material (12), comprising: a conveying apparatus (51) configured to convey objects (2), which are provided for packaging by means of the tubular-bag machine (5), along a conveying direction (6); an apparatus (50, 43) configured to produce, from a packaging sheet material (12), a packaging tube (13) extending in the conveying direction (6); a longitudinal-connection device (53, 54) configured to produce a longitudinal connection of the packaging tube (13) along a longitudinal sheet edge region (120) of the packaging sheet material (12); a transverse-connection device (44) configured to produce transverse connections in the packaging sheet material (12) which extend substantially transversely to the longitudinal connection; and a gas-adjusting device (8) with an introduction head (80) configured to engage in the packaging tube (13) in a direction transverse to the conveying direction, wherein the introduction head (80) has a first gas-passage opening (802, 804, 805, 807, 808) by way of which a gas is fed into the packaging tube (13) or removed therefrom, and wherein the introduction head (80) has at least one second gas-passage opening (802, 804, 805, 807, 808) by way of which a gas is fed into the packaging tube (13) or removed therefrom.
 2. The tubular-bag machine (5) according to claim 1, wherein the introduction head (80) has a longitudinal direction extending in the conveying direction (6) and wherein the second gas-passage opening (802, 804, 805, 808) is disposed downstream of the first gas-passage opening (802, 804, 805, 807) in the longitudinal direction.
 3. The tubular-bag machine (5) according to claim 2, wherein the first gas-passage opening (802) is configured to evacuate air out of the packaging tube (13) and wherein the second gas-passage opening (804, 805, 808) is configured to feed gas into the packaging tube (13).
 4. The tubular-bag machine (5) according to claim 1, wherein the introduction head (80) has a first continuous bearing surface (800) and a second continuous bearing surface (800), wherein the first bearing surface (800) is configured to support a first lateral surface (120) of the packaging tube (13) and the second bearing surface (800) is configured to support a second lateral surface (120) of the packaging tube (13) which lies opposite the first lateral surface (120) and wherein the first gas-passage opening (802, 804, 805, 807, 808) and the second gas-passage opening (802, 804, 805, 807, 808) are disposed between the first and second continuous bearing surfaces (800).
 5. The tubular-bag machine (5) according to claim 4, wherein the introduction head (80) comprises a main section, within which the first bearing surface (800) and the second bearing surface (800) extend substantially parallel to one another and wherein the first gas-passage opening (802, 804, 805, 807, 808) and the second gas-passage opening (802, 804, 805, 807, 808) are disposed in this main section.
 6. The tubular-bag machine (5) according to claim 4, wherein the introduction head (80) has a first wedge-shaped section (801), within which the first bearing surface (800) and the second bearing surface (800) converge in a wedge-shaped manner in a longitudinal direction.
 7. The tubular-bag machine (5) according to claim 2, wherein at least one of the first gas-passage opening (802, 804, 805, 807, 808) and the second gas-passage opening (802, 804, 805, 807, 808) is an elongated hole, which has a substantially larger extension in the longitudinal direction of the introduction head (80) than in a direction perpendicular thereto.
 8. The tubular-bag machine (5) according to claim 1, wherein the introduction head (80) has at least another third gas-passage opening (802, 804, 805, 807, 808) in addition to the first and the second gas-passage opening (802, 804, 805, 807, 808).
 9. The tubular-bag machine (5) according to claim 1, wherein at least one of the first and the second gas-passage opening (802, 804, 805, 807, 808) is configured to evacuate gas out of the packaging tube (13) and is delimited by an orifice structure (806), which is unevenly formed in an opening direction of the first gas-passage opening (802).
 10. The tubular-bag machine (5) according to claim 1, wherein the introduction head (80) has a continuous, substantially planar orifice surface (809), within which the first gas-passage opening (802, 804, 805, 807, 808) as well as the second gas-passage opening (802, 804, 805, 807, 808) outwardly discharges.
 11. The tubular-bag machine (5) according to claim 1, wherein the introduction head (80) has at least one sensor configured to measure gas properties in the packaging tube (13).
 12. The tubular-bag machine (5) according to claim 1, wherein the tubular-bag machine (5) has a control unit (96) which is designed to optimize at least one of a gas feed quantity and a gas removal quantity flowing through the gas-adjusting device (8) as a function of at least one of the following: a volume of the packaging; properties of the objects (2) to be packaged; conveying settings of the conveying apparatus (51); and values which are measured by sensors on the gas-adjusting device (8).
 13. A gas-adjusting device (8) for a tubular-bag machine (5), said gas adjusting device being configured to adjust a gas content of packagings (3) which are produced from a packaging tube (13) by means of a tubular-bag machine (5), the gas-adjusting device comprising: an introduction head (80) configured to laterally engage into the packaging tube (13), wherein the introduction head (80) has a first gas-passage opening (802, 804, 805, 807, 808) by way of which gas is fed into the packaging tube (13) or removed therefrom, and wherein the introduction head (80) has at least one second gas-passage opening (802, 804, 805, 807, 808) by way of which gas is fed into the packaging tube (13) or removed therefrom.
 14. The gas-adjusting device (8) according to claim 13, wherein the introduction head (80) has bearing surfaces (800) for supporting lateral surfaces (120) of the packaging tube (13), wherein the bearing surfaces (800) extend continuously over approximately an entire length of the introduction head (80).
 15. A method for adjusting a gas content of packagings (3) which are produced from a packaging tube (13), which is conveyed in a conveying direction, by means of a tubular-bag machine (5), wherein gas is discharged out of the packaging tube (13) through a lateral opening formed on said packaging tube (13) and wherein gas is simultaneously introduced into the packaging tube (13) through the same lateral opening.
 16. The tubular-bag machine (5) according to claim 6, wherein the introduction head (80) has a second wedge-shaped section (801), within which the first bearing surface (800) and the second bearing surface (800) converge in a wedge-shaped manner in a direction which is oriented oppositely to the longitudinal direction.
 17. The tubular-bag machine (5) according to claim 4, wherein the introduction head (80) has a wedge-shaped section (801), within which the first bearing surface (800) and the second bearing surface (800) converge in a wedge-shaped manner in a direction which is oriented oppositely to a longitudinal direction.
 18. A method for adjusting a gas content of packagings (3) which are produced from a packaging tube (13), which is conveyed in a conveying direction, by means of a tubular-bag machine (5) according to claim 1, wherein gas is discharged out of the packaging tube (13) through a lateral opening formed on said packaging tube (13) and wherein gas is simultaneously introduced into the packaging tube (13) through the same lateral opening. 